Heat the oil in a saucepan. Add mustard seeds, cumin seeds, coriander seeds, cinnamon stick and asafetida and fry until the seeds start to pop.
Add the onion, garlic, turmeric, salt and bay leave. Saute gently until the onion is transparent. Add the cauliflower and water. Stir well, cover and cook 20 minutes until the cauliflower is starting to fall apart.
Remove from heat and stir in the yoghurt and buttermilk. Reheat not quite to a boil. Remove the cinnamon stick and bay leaf, add salt and pepper to taste.